This disclosure relates to polycarbonates comprising aliphatic dihydroxy compounds, and in particular to isosorbide-based polycarbonates, and methods of manufacture thereof.
Polymers based on aliphatic dihydroxy compounds derived from biologically-based sources are of great interest to the plastics industry and to the manufacturing industry, for the preparation of materials and products that can be derived from inexpensive, renewable sources and that also may be biodegradable, and thereby have a low net environmental impact. Of particular interest are polymers based on isosorbides, which are more specifically referred to as 2,6-dioxabicyclo[3.3.0]octan-4,8-dihydroxy compound, 1,4:3,6-dianhydro-D-glucitol, and 2,3,3a,5,6,6a-hexahydrofuro[3,2-b]furan-3,6-dihydroxy compound, and isomers of these. These materials are of great interest to the chemical industry, and in particular in the production of polymeric materials such as polycarbonates, because such aliphatic dihydroxy compounds can be produced from renewable resources, namely sugars, rather than from the petroleum feed stocks used to prepare other monomers useful in the production of polycarbonates, such as bisphenol monomers.
However, for practical applications, polycarbonate incorporating isosorbide needs a balance of properties to be useful. A problem that accompanies inclusion of such biologically derived materials in polycarbonates is maintaining the desired mechanical and optical properties of the polycarbonate during and after high temperature processing, such as encountered during extrusion and molding. Polycarbonates that include isosorbide that otherwise have desirable properties can have insufficient impact and heat resistance properties.
There accordingly remains a need in the art for an isosorbide-based polycarbonate having a sufficiently high heat resistance and impact performance.